1. Technical Field
The present invention relates in general to batteries. More particularly, but without restriction to the particular embodiment and/or use which is shown and described for purposes of illustration, the present invention relates to a acid retention system for a vehicular battery.
2. Discussion
Every motor vehicle includes a battery that is essential to the electrical system of the vehicle. The battery converts electrical current generated by the engine, or more specifically the alternator, into chemical energy that may be stored. The chemical potential energy of the battery can then be harnessed by conversion into the needed electrical current at a later time.
Each battery includes a plurality of positive and negative plates or electrodes immersed in an electrolyte. In a conventional lead-acid battery, the cathode or positive plates typically include lead peroxide (PbO.sub.2) as its active material. The anode or negative plates typically include lead (Pb), and the electrolyte typically includes an aqueous solution of sulfuric acid (H.sub.2 SO.sub.4). The electrodes are connected by an external circuit such that electrons can be transferred therebetween, and thereby create an electrical current.
As electrical current is desired from the battery, energy is released from the battery's stored chemical energy. During this discharge phase the following reactions occur at the anode and cathode, providing a current from the positive to the negative electrode.
Cathode PbO.sub.2 +4 H.sup.+ +SO.sub.4.sup.2- +2e.sup.-.fwdarw.PbSO.sub.4 +2 H.sub.2 O PA0 Anode Pb+SO.sub.4.sup.2- -2e.sup.31 .fwdarw.PbSO.sub.4 PA0 Overall PbO.sub.2 +Pb+2 H.sub.2 SO.sub.4.fwdarw.2 PbSO.sub.4 +2 H.sub.2 O PA0 Cathode 4 H.sub.2 O-4e.sup.-.fwdarw.O.sub.2 +4 H.sup.+ PA0 Anode 4 H++4e.sup.-.fwdarw.2 H.sub.2 PA0 Overall 2 H.sub.2 O.fwdarw.2 H.sub.2 +O.sub.2
As electrical current is stored in the battery, potential chemical energy is created in the battery. During this charging phase the following reactions occur at the anode and the cathode, providing a current from the negative to the positive electrode.
A battery typically will lose some water vapor due to its conversion process and the heat generated by the charging and discharging process. As this water leaves it will take a certain amount of sulfuric acid with it because of the aqueous solution environment. Sulfuric acid in aqueous form is highly corrosive. It can cause premature corrosion of any metal surface that it contacts.
Others have solved this problem in the past by providing drain tubes that direct the aqueous solution to a desired location as is described in U.S. Pat. No. 4,098,366, titled "Device for Mounting A Storage Battery" issued Jul. 4, 1978. Although this apparatus may work satisfactorily in reducing corrosion on neighboring components, there continues to be a need for other inventive apparati that control the aqueous sulfuric acid discharged from a battery.